Guillain-Barré Syndrome: Anterior Root Involvement and Clinical Features

Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy. The primary target is the anterior (ventral) nerve roots and peripheral motor nerves.

Pathophysiology

• Molecular mimicry: Antecedent infection (Campylobacter, CMV, EBV, Zika, influenza, COVID-19) → cross-reactive antibodies attack gangliosides (GM1, GD1a, GQ1b) on axonal membranes.
• Demyelinating (AIDP) or axonal (AMAN/AMSAN) variants.
• Anterior root involvement → flaccid paralysis, areflexia, hypotonia.
• Dorsal roots also affected → sensory loss, pain.
• Autonomic involvement → BP lability, arrhythmia, ileus.

Clinical Features

• Ascending symmetric weakness (legs → arms → respiratory).
• Areflexia (hallmark).
• Albuminocytologic dissociation (↑ CSF protein, normal WBC) after week 1.
• Nerve conduction studies: demyelination (slow CV, conduction block) or axonal loss.

Treatment

• IVIG 2 g/kg over 5 days OR Plasma exchange (5 exchanges).
• Supportive: ICU monitoring (ventilation if FVC <20 mL/kg), DVT prophylaxis, pain control, autonomic management.
• Most recover (6–12 months); 5–10% residual deficit; 3–5% mortality.